import math
x1, y1, x2, y2 = map(float, input().split())
x = abs(x1 - x2)
y = abs(y1 - y2)
xx = x ** 2
yy = y ** 2
zz = xx + yy
z = math.sqrt(zz)
print(round(z, 8))
 import math math x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 x = abs(x1 - x2) x abs(x1 - x2) abs x1 - x2 x1 x2 y = abs(y1 - y2) y abs(y1 - y2) abs y1 - y2 y1 y2 xx = x ** 2 xx x ** 2 x 2 yy = y ** 2 yy y ** 2 y 2 zz = xx + yy zz xx + yy xx yy z = math.sqrt(zz) z math.sqrt(zz) math.sqrt math sqrt zz print(round(z, 8)) print round(z, 8) round z 8 x = abs(x1 - x2) abs(x1 - x2) x zz = xx + yy xx + yy zz y = abs(y1 - y2) abs(y1 - y2) y x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 xx = x ** 2 x ** 2 xx z = math.sqrt(zz) math.sqrt(zz) z y2 = map(float, input().split()) map(float, input().split()) y2 y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 x2, y2 = map(float, input().split()) map(float, input().split()) x2 yy = y ** 2 y ** 2 yy
import math
x1, y1, x2, y2 = map(float, input().split())
x = abs(x1 - x2)
y = abs(y1 - y2)
xx = x ** 2
yy = y ** 2
zz = xx + yy
z = math.sqrt(zz)
print(round(z, 8))

